1. Field of the Invention
This invention relates generally to drive apparatus for propulsion of land vehicles. More specifically, the present invention is directed to a mechanical system that delivers impulse and/or shock energy for propulsion of a land vehicle in the direction of travel.
2. Discussion of Relevant Art
The prior art teaches methods and apparatus for constructing and acquiring front or steering wheel drive for land vehicles, principally bicycles and tricycles. A common thread in such disclosures is the use of pedaling or manual (rotating) energy for intermittent or continuous driving force that is, via mechanical apparatus, transferred to the front wheel. It is this front wheel or steering wheel that is generally used to determine course or direction of the vehicle.
In U.S. Pat. No. 5,158,214, issued to Pinos et al. in 1992, a traction system for a bicycle is disclosed in which a flexible chain system is used to link power, delivered to the rear drive sprocket of a bicycle, with a separate drive means attached to the front wheel (steering wheel) of the bicycle. Conventional sprockets are used in the Pinos et al. disclosure and one differing aspect is (are) the multiplicity of traction chains used for effecting the flexible transmission. A similar dual wheel driven bicycle concept is taught by Becoat in U.S. Pat. No. 5,184,838, issued in 1993. Becoat, however, extracts power from the rear sprocket and transfers it to the front wheel (steering wheel) of the bicycle via an elongate, flexible shaft or cable. Both of the aforesaid teachings appear to achieve the same ends by slightly different means. However, neither are capable of delivering an impromptu stroke or impulse of driving energy (torque) solely to the steering or front wheel of the bicycle. Further, because the steering wheel of both bicycles can never accelerate faster than the rear (drive) wheel, both the Pinos and the Becoat bicycles allow their operators no distinctive advantage when executing a turn.
The above patents fall into, what I define as, the pedal or pedaling drive category of driven steering wheels. Another category is that wherein the steering wheel of the vehicle is manually powered, generally by the hands and upper torso of the body. One of the earliest of such devices was disclosed by Schaibly in U.S. Pat. No. 613,943 issued in 1898. The Schaibly device was a conventional bicycle which employed a hand-driven crank connected to a front wheel driving sprocket so that the hands of the rider could, by a rocking motion, propel the front wheel of the bicycle. A distinct disadvantage of the Schaibly apparatus was that front wheel propulsion could not be effected while the operator of the bicycle was pedaling, thus transferring power only to the rear wheels. At such time, the intricate rocking drive mechanism for the front wheel served exclusively as a steering assembly for the bicycle. A later version of the Schaibly art is disclosed in U.S. Pat. No. 3,823,959, issued in 1974 to Winters. Winters employed a hand "pedaling" apparatus that was an adjunct to the primary steering assembly (a set of traditional, although slightly elevated handle bars). In the Winters teaching, a hand propelled crank is rigidly bolted to the vertical steering stem of the bicycle and a chain is used to take off power therefrom and deliver it down-stem to a conventional driving sprocket which serves as the hub of the front, steering wheel. The remaining portion of the Winters disclosure, like the Schaibly before it, is simply incapable of providing the performance needed for delivering a rapidly or impulsively generated power stroke to the steering wheel.
U.S. Pat. No. 4,417,742, issued in 1983 to Intengan discloses the combined the cable transmission idea of Becoat with the hand motivated front wheel drive of Winters, having avoided the necessity of a handle bar set by integrating the hand crank with a steering arm assembly, so that the steering wheel (front wheel) turned in response to an azimuthal change in the steering arm assembly.
Use of a multiple-drive vehicle such as a bicycle, tricycle and three-or four-wheeled, all-terrain vehicle in a competitive or off-road environment, many times requires an acutely executed turn. During such turns, a steering wheel which has independent rotational movement from the other wheel is necessary. If the steering wheel is rigidly affixed to the other wheel by gear drive mechanisms, then the drive mechanism will break or require excessive slippage.